196 Miscter — Fortnation of the Oxides of Cobalt and Nickel. 



peroxide 20 grains. Thermal eli'eet for 1 grain of cobalt 

 1031)^- and 104(K. For 59 grams, 61,360^ 



The fusions disintegrated slowly in cold water with evolu- 

 tion of oxygen. The insoluble black residue contained sodium, 

 water and a ])eroxide. 



3. Heat of reaction of coT)altous-col)altic oxide with sodium, 

 peroxide. — Cobaltous-cobaltic oxide, prepared from carbonate 

 by heating in air, yielded very nearly the theoretical amount 

 of metal when reduced by hydrogen. It was in the form of a- 

 bulky powder. 



Experiment 8. — Cobaltous-cobaltic oxide 6*000, sulphur 

 1*000, sodium peroxide 15 grams. Heat effect of 1 gram 

 Co,0, 286^ 



Experiment 9. — Cobaltous-cobaltic oxide 9*000, sulphur 

 1*500, sodium peroxide 22 grams. Heat effect of 1 gram 

 Co,0, 282^ 



The fusions were good and gave off much oxygen when 

 placed in cold water. The black residue left by water 

 retained alkali after prolonged digestion and washing with 

 water. Aftei' remaining for several days in a vacuum over 

 sulphuric acid it was found to yield water and oxygen when 

 heated. The average of the two results is 284^ For a gram 

 molecule of CO3O, it is 68,444^. 



4. Heat of reaction of cohaltous oxide with sodium pe7'- 

 oxide. — Amorphous cobaltous oxide was prepared by heating 

 the carbonate in a current of dry carbon dioxide. The follow- 

 ing are the experiments : 



Experiment 10. — Cobaltous oxide 8*000, sulphur 1*000, 

 sodium peroxide 18 grams. Heat effect of 1 gram cobaltous 

 oxide 394^ 



Experiment 11. — Cobaltous oxide 10*266, sulphur 1*000, 

 sodium peroxide 21 grams. Heat effect of 1 gram of cobalt- 

 ous oxide 414^ 



The average of the two results, 404<=X75 = 30,390<=. 



Summary of Results on Cobalt. 



Co + O = CoO (crystalline) -f- 57*5^^ 



Co -F O = CoO (amorphous) + 50*5^^ 



3Co -h 40 = CO3O, -I- 193*4'= 



3 CoO (amor.) -t- O = CO3O, -f 41*9'= 



Co -I- 2Na^0^ = Na^CoO, + Na^O H- 61*4'= 



2NajO -f 20 = 2]Sra^0, + SS-S-^ 



Co -F 20 -h Na„0 = Na,Co03 + 100*2<= 



Co,0, -f- 2Na^0, + Na^O = 3Na^Co03 + 68*4<= 



2Na^O + 20 = 2]Sra^0, + 38*8"= 



Co.O, -f 20 -F 3Na,0 = 3Na,Co03 -t- 107*2^^ 



